I've absolutely no idea about what kind of drawings a child should do at different ages. I don't know if there are different expectations in terms of accuracy or different styles that come in at different ages. But I just wanted to say I'm an artist and I really really like this drawing.
I love the use of colour and the energy and I really love the humour in it. The cat up the tree is class! As an overall picture it is really fun and humorous and I'd have loved to get something like that.
Children get an idea in their heads that they are good at this and bad at that. Then give up on the things they feel they were "bad" at which could have added so much to their lives in terms of fun or focus or expression. It becomes a thing where they don't enjoy a certain thing as it makes them feel bad. But drawing is for everyone, at any age. I was considered very good at drawing as a child but I think largely the reason is I did it a lot and the reason for that is that it was my thing and I had lots of access to pens and paints and paper and I could do what I wanted. I also had access to books of paintings which was inspiring. Thinking back a lot of my friends had no paper lying about all over the place or access to other artworks to look at. It just wasn't a part of their lives really.
School demands a certain thing artwise. Then later on you find there are a tonload of people out there who can draw fairly representationally but get stuck just doing fairly representation studies and not doing anything with it, perhaps forever. The key thing is having your own thing you enjoyr or say or do with it. The other thing is that people who are great at drawing are not always that good at painting and vice versa. We get obsessed with lines around things in drawing. Whereas painting is about colour and boldness and not about the lines.
I love the use of the colours and blocks of vibrant and energetic felt tip in this. I like the way it's not about lines but about those blocks of colour. I adore the humour.
Perhaps try giving him more detailed feedback and encouragement. Maybe do some drawing with him so he can see it's fun rather than something from school that he feels bad about. Please don't let him get so down on himself about a great drawing that was a beautiful and fun gift.
Maybe he doesn't want to draw, but the sadness you describe about his attitude to his drawing is heartbreaking when I'm looking at such a lively and zingy piece.